Peanut allergy is known to cause severe anaphylactic reactions. Compared with other food allergies it tends to be more persistent and also its prevalence seems to be rising. Currently there is no proven treatment other than strict avoidance. We are attempting to decrease the risk of anaphylaxis on accidental ingestion by desensitizing subjects to peanut using peanut mucosal immunotherapy (MIT). We are also studying the effect of peanut MIT on the peanut specific immune response to determine if tolerance to peanut protein will develop. Children ages one to six with peanut allergy will be randomized to peanut MIT or placebo. Subjects will undergo a modified rush immunotherapy on the first day and then increase the doses at least every two weeks up to a maintenance dose of 4 grams (equivalent to about 13 peanuts). Doses will be taken daily at home except for dose increases which will be done on the DCRU. Outcome variables of interest include response to double-blind placebo controlled food challenge, skin prick testing, peanut specific IgE, and adverse events. These results will be compared between the start and end of peanut MIT using appropriate statistical analysis.

Inclusion Criteria:

• Subject between 1 and 6 years of age

• Diagnosed peanut allergy by RAST greater than or equal to 15 within past 6 months and have eaten peanut in diet resulting in a clinical reaction prior to diagnosis

• Diagnosed peanut allergy by RAST greater than or equal to 7 within past 6 months and have had a clinical reaction to peanut ingestion within the past 6 months

Exclusion Criteria:

• Subjects with a history of severe, anaphylaxis to peanut

• Medical history that would prevent a DBPCFC/OFC to peanut